What Is Wrong With My Grannyvine?

Are there any small, round reddish brown spots with white to grey centers on the upper surface of the leaves?

Are there any soft, water-soaked spots on the stems?

Are there any rust-colored spots on foliage?

Do the leaves have pale areas on upper surfaces and "downy" patches underneath?

Are the leaves discolored, fine webbing may be present?

Are the leaves curled and distorted?

Do the leaves have holes?

Do the leaves wilt, curl and turn brown, usually in the shaded part of the plant?

These symptoms indicate Alternaria leaf spot. Warm, wet conditions favor this fungal disease. Spray infected plants with copper and/or sulfur to prevent further disease development. Plant only pathogen-free seed from a reputable nursery.

Soft, water-soaked spots on stems are caused by Stem rot. This disease can be caused by both bacterias and fungi. Remove and destroy all infected plants. Thin plants to ensure good airflow. Water your plants from below. Keep mulch a few inches away from stems. In cases of severe infestations, don't replant new grannyvines in affected areas.

Rust-colored spots on foliage indicate a fungal disease - Rust. Provide good air circulation around plants by thining them. Avoid making leaves wet when watering. All infected leaves should be removed. Spray leaves with sulfur early in the season to prevent rust or to treat mild infections.

Pale areas on upper surfaces of the leaves and "downy" patches underneath are caused by Downy mildew. This fungus spreads quickly during cool, wet nights and warm, humid days. Leaves will wilt and die. Remove and destroy all affected plant parts and encourage good air circulation around plants by thining them. Water plants early in the morning to make sure they dry before nightfall.

Spider mites are known to cause problems for grannyvines. Hose off plants when symptoms first appear. A strong stream knocks mites off plants and may give control. Introduce predatory mites. For severe infestations, spray plants with insecticidal soap or pyrethrin.

Distorted and curled leaves are caused by aphids. These tiny insects cluster under leaves and on growing tips where they feed on plant sap. Leaves, stems, and buds get distorted and later leaves and flowers drop from the plant. You can control them by washing them off the plant with water spray. Insecticidal soap should be used with severe infestations.

Various caterpillars will feed on grannyvine leaves. They may also feed on stems and flowers. Handpick and destroy caterpillars, or spray plants with BTK if caterpillars are feeding.

Thread blight is a fungal disease that makes leaves wilt and turns brown, usually in the interior or shaded portions of the vine. Dead, curled leaves cling to blighted branches, frequently in mid-branch, with unaffected leaves still appearing on both sides of the diseased area. Pruning to promote better penetration of sunlight and air movement may help. Prune out infected twigs and branches may provide adequate control.

If there are tunnels in leaves the culprits are leafminers. These tiny fly larvae feed within the leaves in meandering mines that become wider as the larvae grow. Prune off and destroy all infested leaves. Remove debris in fall because it might contain overwintering leafminers. Introducing parasitic wasps is a very effective method of controlling leafminers.